The IDTV implies that the audience not only can watch the video of a digital TV program, but also can control the IDTV contents attached in the program through the remote control, keyboard, or mouse. The IDTV contents may be computer program codes, or data in some formats. For example, the digital video broadcasting (DVB) standard association in Europe proposed the Multimedia Home Platform (MHP), which uses IDTV contents of Java program code. European Telecommunication Standards Institute (ETSI) proposed Worldwide TV Markup Language (WTVML), which uses eXtensible Markup Language (XML) as the IDTV content format. The conventional IDTV is designed for a single screen, and the IDTV contents and digital TV program videos share the same screen space.
On the other hand, the dual-screen IDTV system implies that the audience has a shared screen which is only for displaying the videos, and is located at the host IDTV end. FIG. 1 shows a schematic view of an exemplary dual-screen IDTV. As shown in FIG. 1, host IDTV 101 may be the combination of a set-top box and a TV screen, an integrated digital TV, or the combination of a PC and a monitor. In addition, each audience has a handheld device, marked as 105a-105d. The handheld device may be PDA or smart phone.
In the dual-screen IDTV, host IDTV 101 and handheld devices 105a-105d use wired or wireless transmission medium for communication. The dual-screen IDTV allows each audience to use the handheld device to select the DTV contents. In principle, only one video of the DTV contents can be displayed on the display of the host IDTV.
FIG. 2 shows the structure and the operation of an exemplary dual-screen IDTV. As shown in FIG. 2, DTV content 204 is transmitted by application service provider (ASP) 201 to broadcaster 203. Broadcaster 203 may be terrestrial digital TV station, cable multiple service operator (MSO), satellite digital TV station, or IPTV operator. Broadcaster 203 uses MPEG-2 or IP protocols to broadcast or multicast DTV contents 204 through terrestrial radio, cable, satellite, or broadband network to host IDTV 101. Host IDTV 101 may also obtain auxiliary data and computer program from a network 207 other than digital broadcasting network, such as Internet, to integrate with the DTV contents 204 from the digital broadcasting network, and then use the integrated information.
DTV contents 204 include video and audio (AV) contents, host IDTV contents, and handheld IDTV contents. When a TV viewer uses a handheld device to select a DTV content, host IDTV 101 will keep the relevant host IDTV content in received DTV content 204 on host IDTV 101 for execution. The relevant handheld IDTV content will be transferred to the handheld device. During the process, the AV contents in DTV contents 204 may also be selectively transferred to the handheld device, and the AV contents may be trans-coded based on the context of the handheld device. The context includes the screen size, supported AV decoder, and so on. While the DTV content is in execution, the host IDTV contents and the handheld IDTV contents will use a certain protocol to synchronize the content state so that the execution states in both contents will be the same.
In the single-screen IDTV, the development of the IDTV contents usually relies on the authoring tool for IDTV contents to reduce the writing of the program code and simplify the IDTV content production. However, the single-screen IDTV has only one display screen, which allows only one TV viewer to operate the IDTV contents at a time. Although dual-screen can solve the above problem, the problems of context diversity and the lack of authoring tool remain the major obstacle for implementing dual-screen IDTV.
The handheld devices, such as PDA and smart phones, have different contexts, including screen sizes and input interfaces. Since it is almost impossible for programmers to maintain a version of computer program for each type of handheld device, a user interface technology that is adaptive and context-aware is required. Furthermore, the lack of standard for the dual-screen IDTV technology also results in the lack of readily available IDTV content authoring tools.
The modality-independent remote console technology may solve the problem of context diversity of handheld devices. The AIAP-URC (Alternate Interface Access Protocol-Universal Remote Console) standard of ANSI (American National Standards Institute) is a classic example of the modality-independent remote console technology. The AIAP-URC standard uses a language based on XML to describe an abstract user interface. The abstract description is mainly the information on the functions of the user interface, and optionally includes the presentation hint for the user interface. However, the detailed presentation information of the user interface is not included.
As the user interface of the TV remote control shown in FIG. 3, the abstract description of the user interface in the form of AIAP-URC standard includes the information on commands, variables, labels, and groups. The abstract user interface description includes three groups: numeric button group 311, volume control button group 313, and channel selection button group 315. Power button 317, numeric buttons (0-9), volume control buttons (+ and −), and channel selection buttons (+ and −) belong to the command information. Text message display 303 is the variable information. The capital “V” of the volume control button group and the capital “P” of the channel selection button group are the label information.
For different handheld devices, the abstract user interface description of the TV remote control in FIG. 3 can be translated into a physical/concrete user interface displayed on the handheld device according to the context, such as screen size, GUI function, and so on. Therefore, the TV remote controls displayed on different handheld devices may look different, while have the same functionality. In this manner, the context diversity problem can be overcome.
Europe Patent No. EP1659487 disclosed a method and apparatus for exchanging data between computer system and auxiliary displays. The system includes a main computer system and one or more auxiliary display devices. The application programs on the main computer system may use a unified API to treat different auxiliary display devices as user interfaces. The user interface can display the information for the user to read in order to remotely control the applications on the main computer system, or display the message notification issued by the applications. Each auxiliary display device has a dedicated display device driver on the main computer system. The display device driver will dynamically filter out the media contents that the auxiliary display device cannot display. With this method, the difference among the different auxiliary display devices will be hidden by the display device driver.